Sakakibara works with tree automata to model the derivation trees of the unknown grammars [1]}.
In our case the automaton needs to associate a weight with every tree (representing a structured string). We choose to work with the model of multiplicity tree automata. A multiplicity tree automaton (MTA) associates with every tree a value from a given field \(\mathbb {K}\) . An algorithm for learning multiplicity tree automata, to which we refer as \({\textbf {M}^*}\) , was developed in [2]}, [3]}.Following a learning algorithm developed for multiplicity word automata [4]}, [5]}.
